Alert archive / Iowa / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 102, NWS Quad Cities, IA
NWS Quad Cities, IA issued this severe thunderstorm warning at Aug 26, 2021, 9:58 PM CDT for Keokuk County, Iowa. It was in force for 47 min. 8 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 26, 2021, 9:58 PM CDT (02:58 UTC)
- Expired
- Aug 26, 2021, 10:45 PM CDT
- In force
- 47 min
- Issued by
- NWS Quad Cities, IA
- Area
- Storm-based polygon
- Damage threat
- Considerable
- Hail
- 0.75 in
- Wind
- 70.0 mph
County Keokuk County, IA
The radar
The Des Moines radar (KDMX), 128 km from the middle of the area, began a volume at 02:59 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 26, 10:20 PM CDT | TSTM WND DMG | Delta, IA | SHERIFF OFFICE REPORTS 2 TO 3 TREES DOWN ACROSS ROADS IN DELTA. |
| Aug 26, 10:25 PM CDT | TSTM WND DMG | 2 N Lancaster, IA | ROOF BLOWN OFF A BARN AT EM PROPERTY. TIME ESTIMATED. |
| Aug 26, 10:30 PM CDT | TSTM WND GST 72 | Sigourney, IA | MEASURED BY IDOT RWIS. |
| Aug 26, 10:40 PM CDT | TSTM WND GST 72 | 2 N Lancaster, IA | WEATHER STATION AT EM RESIDENCE. |
| Aug 26, 10:47 PM CDT | HAIL 1 | 1 Wnw Sigourney, IA | TIME ESTIMATED FROM RADAR, DELAYED REPORT. |
| Aug 26, 10:48 PM CDT | HAIL 1.75 | Sigourney, IA | . |
| Aug 26, 10:49 PM CDT | HAIL 1.5 | 2 N Sigourney, IA | MIX OF HAIL SIZES FROM PENNIES TO PING PONG BALL. |
| Aug 26, 10:51 PM CDT | TSTM WND DMG | Sigourney, IA | NUMEROUS 2.5 INCH TREE LIMBS DOWN ACROSS TOWN WITH TWO LARGE TREES DOWN. TIME OF THE EVENT ESTIMATED USING RADAR. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Davenport, (KDVN), launched 00:00Z, 3.0 hours before the alert went out and 150 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 673 J/kg
- Mixed-layer CIN
- -189 J/kg
- Mixed-layer LCL
- 1469 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- -106 m²/s²
- 0-3 km storm-relative helicity
- -64 m²/s²
- Significant tornado parameter
- -0.0
- Supercell composite
- -1.7
The text
As transmitted.
780
WUUS53 KDVN 270258
SVRDVN
IAC107-270345-
/O.NEW.KDVN.SV.W.0102.210827T0258Z-210827T0345Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Quad Cities IA/IL
958 PM CDT Thu Aug 26 2021
The National Weather Service in the Quad Cities has issued a
* Severe Thunderstorm Warning for...
Keokuk County in southeastern Iowa...
* Until 1045 PM CDT.
* At 958 PM CDT, a severe thunderstorm was located over What Cheer,
or near Sigourney, moving southeast at 25 mph.
HAZARD...70 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect considerable tree damage. Damage is likely to
mobile homes, roofs, and outbuildings.
* This severe thunderstorm will be near...
Sigourney around 1015 PM CDT.
Other locations in the path of this severe thunderstorm include
Hayesville and Martinsburg.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
sturdy building.
Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4151 9241 4151 9224 4133 9196 4118 9206
4118 9235 4129 9241
TIME...MOT...LOC 0258Z 321DEG 21KT 4140 9230
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH
$$
Gibbs5 follow-up statements
102
WWUS53 KDVN 270302
SVSDVN
Severe Weather Statement
National Weather Service Quad Cities IA/IL
1002 PM CDT Thu Aug 26 2021
IAC107-270345-
/O.CON.KDVN.SV.W.0102.000000T0000Z-210827T0345Z/
Keokuk IA-
1002 PM CDT Thu Aug 26 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1045 PM CDT
FOR KEOKUK COUNTY...
At 1001 PM CDT, a severe thunderstorm was located near What Cheer, or
near Sigourney, moving southeast at 25 mph.
HAZARD...70 mph wind gusts and ping pong ball size hail.
SOURCE...Radar indicated.
IMPACT...People and animals outdoors will be injured. Expect hail
damage to roofs, siding, windows, and vehicles. Expect
considerable tree damage. Wind damage is also likely to
mobile homes, roofs, and outbuildings.
This severe storm will be near...
Sigourney around 1010 PM CDT.
Other locations in the path of this severe thunderstorm include
Hayesville and Martinsburg.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.
To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
the Quad Cities.
Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4151 9241 4151 9224 4133 9196 4118 9206
4118 9235 4129 9241
TIME...MOT...LOC 0301Z 321DEG 21KT 4138 9228
TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.50 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH
$$
Gibbs669
WWUS53 KDVN 270311
SVSDVN
Severe Weather Statement
National Weather Service Quad Cities IA/IL
1011 PM CDT Thu Aug 26 2021
IAC107-270345-
/O.CON.KDVN.SV.W.0102.000000T0000Z-210827T0345Z/
Keokuk IA-
1011 PM CDT Thu Aug 26 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1045 PM CDT
FOR KEOKUK COUNTY...
At 1011 PM CDT, a severe thunderstorm was located near Sigourney,
moving southeast at 15 mph.
HAZARD...Golf ball size hail and 70 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...People and animals outdoors will be injured. Expect hail
damage to roofs, siding, windows, and vehicles. Expect
considerable tree damage. Wind damage is also likely to
mobile homes, roofs, and outbuildings.
Locations impacted include...
Sigourney, Hayesville and Harper.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.
To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
the Quad Cities.
Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4151 9241 4151 9224 4133 9196 4118 9206
4118 9235 4129 9241
TIME...MOT...LOC 0311Z 317DEG 14KT 4138 9227
TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH
$$
Gibbs012
WWUS53 KDVN 270319
SVSDVN
Severe Weather Statement
National Weather Service Quad Cities IA/IL
1019 PM CDT Thu Aug 26 2021
IAC107-270345-
/O.CON.KDVN.SV.W.0102.000000T0000Z-210827T0345Z/
Keokuk IA-
1019 PM CDT Thu Aug 26 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1045 PM CDT
FOR KEOKUK COUNTY...
At 1019 PM CDT, a severe thunderstorm was located over Sigourney,
moving southeast at 25 mph.
HAZARD...Golf ball size hail and 70 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...People and animals outdoors will be injured. Expect hail
damage to roofs, siding, windows, and vehicles. Expect
considerable tree damage. Wind damage is also likely to
mobile homes, roofs, and outbuildings.
Locations impacted include...
Sigourney, What Cheer, Delta, Keswick, Harper, Martinsburg,
Hayesville, Ollie, Webster, Thornburg, Gibson, Lancaster, Coal Creek,
Keokuk County Expo, Lake Belva Deer Park, Yenruogis County Park and
Keokuk County Fairgrounds.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.
To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
the Quad Cities.
Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4151 9241 4151 9224 4133 9196 4118 9206
4118 9235 4129 9241
TIME...MOT...LOC 0319Z 321DEG 21KT 4134 9223
TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH
$$
Gibbs492
WWUS53 KDVN 270324
SVSDVN
Severe Weather Statement
National Weather Service Quad Cities IA/IL
1024 PM CDT Thu Aug 26 2021
IAC107-270345-
/O.CON.KDVN.SV.W.0102.000000T0000Z-210827T0345Z/
Keokuk IA-
1024 PM CDT Thu Aug 26 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1045 PM CDT
FOR KEOKUK COUNTY...
At 1024 PM CDT, a severe thunderstorm was located over Sigourney,
moving southeast at 25 mph.
HAZARD...Golf ball size hail and 70 mph wind gusts.
SOURCE...Law enforcement.
IMPACT...People and animals outdoors will be injured. Expect hail
damage to roofs, siding, windows, and vehicles. Expect
considerable tree damage. Wind damage is also likely to
mobile homes, roofs, and outbuildings.
Locations impacted include...
Sigourney, What Cheer, Delta, Keswick, Harper, Martinsburg,
Hayesville, Ollie, Webster, Thornburg, Gibson, Lancaster, Coal Creek,
Keokuk County Expo, Lake Belva Deer Park, Yenruogis County Park and
Keokuk County Fairgrounds.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.
To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
the Quad Cities.
Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4151 9241 4151 9224 4133 9196 4118 9206
4118 9235 4129 9241
TIME...MOT...LOC 0324Z 321DEG 21KT 4132 9220
TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...70 MPH
$$
Gibbs279
WWUS53 KDVN 270334
SVSDVN
Severe Weather Statement
National Weather Service Quad Cities IA/IL
1034 PM CDT Thu Aug 26 2021
IAC107-270345-
/O.CON.KDVN.SV.W.0102.000000T0000Z-210827T0345Z/
Keokuk IA-
1034 PM CDT Thu Aug 26 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1045 PM CDT
FOR CENTRAL KEOKUK COUNTY...
At 1034 PM CDT, a severe thunderstorm was located near Hayesville, or
near Sigourney, moving southeast at 25 mph.
HAZARD...Golf ball size hail and 70 mph wind gusts.
SOURCE...Law enforcement.
IMPACT...People and animals outdoors will be injured. Expect hail
damage to roofs, siding, windows, and vehicles. Expect
considerable tree damage. Wind damage is also likely to
mobile homes, roofs, and outbuildings.
Locations impacted include...
Sigourney, What Cheer, Delta, Keswick, Harper, Martinsburg,
Hayesville, Ollie, Webster, Lancaster, Keokuk County Expo, Lake Belva
Deer Park and Yenruogis County Park.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.
To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
the Quad Cities.
This is a dangerous storm, capable of producing large hail driven by
severe winds! SEEK SHELTER NOW inside a sturdy structure and stay
away from windows! If you are caught outdoors, cover your head and
neck.
Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4143 9233 4151 9224 4133 9196 4118 9206
4118 9235 4129 9241
TIME...MOT...LOC 0334Z 321DEG 21KT 4127 9215
TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...70 MPH
$$
GibbsThe office that day
Everything else NWS Quad Cities, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 26, 8:23 PM CDT | Special Weather Statement | DVN | Benton | 52 min |
| Aug 26, 9:21 PM CDT | Severe Thunderstorm Warning | DVN | Iowa, Keokuk | 39 min |
| Aug 26, 10:29 PM CDT | Flash Flood Warning | DVN | Keokuk | 4 hr |
| Aug 26, 10:43 PM CDT | Severe Thunderstorm Warning | DVN | Keokuk, Washington | 47 min |
| Aug 26, 10:57 PM CDT | Severe Thunderstorm Warning | DVN | Jefferson, Washington | 48 min |
| Aug 26, 11:20 PM CDT | Tornado Warning | DVN | Jefferson, Keokuk | 27 min |
| Aug 26, 11:39 PM CDT | Severe Thunderstorm Warning | DVN | Jefferson, Washington | 31 min |
| Aug 27, 1:34 PM CDT | Heat Advisory | DVN | Lee | 29 hr |
| Aug 27, 3:07 PM CDT | Heat Advisory | DVN | Des Moines, Henry, Van Buren | 28 hr |
Nearby
Severe Thunderstorm Warnings in Iowa, 2021Every severe thunderstorm warning in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.